Move vlog option descriptions into a separate file lib/vlog.man that
is substituted into manpages.
Get rid of individual rules for substituting most files in favor of
a single suffix rule. Unfortunately this loses the (Emacs-specific)
read-only markings but it simplifies the makefiles.
Make "make" behave properly when these are changed by re-running
"configure", by putting their definitions into a generated file that
depends on Makefile.
One use case is when NOX is running on localhost, in which case waiting
for the full default backoff interval is unnecessary and undesirable.
Also changes default maximum backoff to 15 seconds (from 60).
Ben Pfaff
Justin Pettit